Power transmission mechanism



July 23, 1940. w. s, HOFFMAN 2,209,120

POWER TRANSMISSION MECHANISM Filed June 29, 1939 2 Sheets-Sheet l n1 Q I a W H I I 3 x? 1 I J' L 1 I 2m w k I g Q q IPW anmm I &

g l Ml W July 23, 1940. w. G. HOFFMAN POWER TRANSMISSION MECHANISM Sheets-Sheet Filed June 29, 1939 Patented July 23, 1940 UNITED STATES PATENT OFFICE- 2,209,120 rowan TRANSMISSIONMECHANISM William G. Hoffman, Baltimore, Md.

Application June 29, 1939, Serial No. 281,975

My invention relates to power transmission ried by pins or studs I2 projecting laterally mechanism of the type having a speed changing from one side of a disk i2 with which the inner unit and it has for its principal object the proend of shaft 5 is integrally formed. Surrounding vision of means whereby thespeed changing unit the planet gears I is an internally toothed ring will be substantially free of or subjected to only gear I4 which is preferably formed integrally a minimum of eccentric stresses should the axes with one part of a two-piece housing I! enclosing of the driving and driven members with. which the speed changing unit. The opposite sides of the unit is associated be out of alignment. the housing are provided with concentrically A primary feature of the invention consists arranged openings it through which the shafts in connecting a speed changing unit of the 5 and '6 respectively extend, the shafts being planetary gear type to driving and driven memjournaled in' the openings in any convenient bers by flexible couplings which constitute the manner as by bearings H. The meeting faces sole support of the unit and in also providing of the two parts of the housing ii are preferably means for restraining movement of the internally stepped or shouldered, as indicated at I8, so that toothed ring gear of the speed changing unit to the bolts I9 by which the two parts of the hous- 1| enable the latter to transmit power, said means ing are rigidly connected will not be subject to being of a character permitting the axis of the shearing strains. To enable the speed changing unit to move angularly with respect to the axes unit to transmit power imparted to it means, to

of the driving and driven members. be hereinafter described, is provided for re- Other and more specific features of the instraining rotation of the ring gear i4. 90 vention, residing in advantageous forms, com- The coupling members 20 which may adbinations and relations of parts, will hereinafter vantageously be employed for connecting the appear and be pointed out in the claims. speed changing unit to shafts z and 3 and whi h In the drawings, constitute the sole support for the unit are of 2 Figure 1 is a view partly in side elevation and identical construction and each includes a pair a partly in section illustrating the preferred emof hubs 2| and 22 respectively, which are rigidly bodiment of the invention. secured in any suitable manner (not shown) to Figure 2 is a sectional view taken on line 2-2 the shafts on which they are respectively of Figure 1. mounted. Instead of mounting hubs 2| on Figure 3 is a sectional view taken on line I-3 shafts 5 and 9, respectively, and hubs 22 on shafts of Figure 1. 2 and 3, respectively, it is preferred that hubs Referring more particularly to the drawings, 2| be mounted on the latter shafts and hubs 22 l indicates a speed changingunit of the planetary on the former shafts. Each of hubs 22 is formed gear type and 2 and 3 respectively indicate the on its periphery with gear teeth 23 which mesh shafts or members with which the speed changwith teeth 24 formed on the interior of a sleeve 3 ing unit is associated. Each of the shafts is, 25 which encircles hub 22 and is rigidly conjournaled in a suitably located bearing 4. Shaft nected to hub 2| by bolts 26. Being thus geared 2 may be the member by which power is transtogether, the hubs function as a rigid unit to mitted through the speed changing unit to shaft transmit rotary motion between the shafts which 3 in which event shaft 2 will be the driving memthey a couple and at the same time they enable 40 her and shaft 3 the driven member, or shaft 9 the axis of shafts 5 and 6 to angle slightly with may be the member by which power is transrespect to the axes of shafts 2 and 3, so as to mitted through the speed changing unit to shaft compensate for misalignment of the latter with- 2 in which event shaft 3 will be the driving memout subjecting any of the shafts to a reversal her and shaft 2 the driven member. of stresses. As the couplings constitute the sole 45 The speed changing unit has oppositely exsupport for the speed changing unit, it will be tending shafts 5 and 6, the outer ends of which evident that the unit is free, unless restrained by are coupled, by means to be hereinafter desome external force, to assume a neutral posiscribed, to the shafts 2 and 3. Shaft 6, whose tion, that is a position in which it will be subinner end is supported in a suitable bearing such stantially free of or at the most will be subjected 50 as a roller bearing 1 disposed within a recess 8 to only a minimum of eccentric forces. in the inner end of shaft 5, is rigidly provided To prevent the setting up of external forces with a pinion or sun gear 9 which is in mesh which might keep the speed changing unit from with a plurality of pinions or planet gears lli assuming a neutral position, the means which is 56 revolubly mounted on suitable bearings Ii caremployed for restraining movement of the in- .ternally toothed ring gear I l is of such character 11 shown) and connected at its other end by a link II to a yoke 29 which is connected to the housing II with which the ring gear I! is integrally formed, By providing a flexible means of this character for restraining rotation of the ring 1 ll gear, it will be perceived that not only is the axis of the speed changing unit enabled to move angularly but it will have a dampening effect on the driving torque initially transmitted to theunit.

iao WhatIclaimis:

1. Power transmission mechanism including a driving shaft, a driven shaft, a speed changing unit of the planetary gear type having an internally toothed ring gear adapted to be, restrained against rotation to enable said unit to transmit power, said unit being operatively interposed between the driving and driven shafts and having oppositely extending shafts, flexible couplings respectively connecting the driving and driven shafts to said oppositely extending shafts, said couplings constituting the sole support of said speed changing unit, and means for restraining rotation of the ring gear of the speed changing unit, said means and flexible couplings enabling the speed changing unit to assume a position with respect to the driving and driven shafts such that it will be subject to a minimum of eccentric stresses.

2. Power transmission-mechanism including a driving shaft, a driven shaft, a speed changing unit of the planetary gear type having an internally toothed ring gear adapted to be restrained against rotation to enable said unit to transmit power. said unit being operatively interposed between the driving and driven shafts and. having oppositely extending shafts, flexible couplings respectively connecting the driving and driven shafts to said oppositely extending shafts, said couplings constituting the sole support of said speed changing unit and each including a peripherally toothed hub rigid with one-of the shafts to be coupled and a hub rigid with the other shaft having an interiorly toothed sleeve portion encircling the first named hub and in of the planetaryv gear type having an internallytoothed ring, gear adapted to be restrained against rotation to enable said unit to transmit power, flexible couplings respectively connecting said oppositely extending shafts to the driving and driven shafts, said couplings constituting the sole support of said speed changing unit and each including a peripherally toothed hub rigid with one of the shafts to be coupled and a hub -rigid with the other shaft'having an interiorly toothed sleeve portion encircling the first named hub and in mesh, with the teeth thereof, and flexible means connected to said ring gear for restraining rotation thereof, said flexible means being capable of permitting the axis of the speed changing unit to move angularly with respect to the axes of the driving and driven shafts.

' WILLIAM G. HOFFMAN. 

